Aluminum Suspension Component Serviceability

Aluminum Suspension Component Serviceability

For every 10 percent reduction in vehicle weight, there is a 5 to 7 percent fuel savings. Since 1990, there has been a steady increase in the weight of vehicles due to airbags, structural components and convenience features like heated seats. This fattening in some areas forced suspension components to go on a diet.

For every 10 percent reduction in vehicle weight, there is a 5 to 7 percent fuel savings. Since 1990, there has been a steady increase in the weight of vehicles due to airbags, structural components and convenience features like heated seats. This fattening in some areas forced suspension components to go on a diet. 
 

One additional benefit of aluminum suspension components is their noise and vibration dampening properties. Engineers have found that aluminum transmits less road and tire noise to the passenger compartment due to the density of the material.
 
The most important benefit is the reduction in unsprung weight. By reducing weight that connected to the suspension, handling increased while allowing for a more comfortable ride by using lower spring rates and dampener valving. 
This is why more and more vehicles entering your shop will have more aluminum suspension components.
Inspection
In most cases, an aluminum component is as strong or stronger than steel or cast iron. But what sets aluminum apart is how it fails. Most aluminum suspension components are forged and heat-treated. If a component has undergone extreme stress like a curb strike, it will most likely crack and break instead of bend. 
 
If you have a vehicle in your bay that has been in a crash or has had a curb strike, look for cracks. There are dye kits on the market to help you inspect for cracks. These kits are easy to use and can spot unseen cracks.
 
Never try to weld aluminum suspension components. Aluminum is more heat sensitive than iron or steel. The heat from welding can ruin the temper of a component and make it more brittle. 
 

The Hyundai Genesis platform uses aluminum in the knuckle and upper strut tower.

When inspecting a vehicle with aluminum control arms, pay special attention to the ball joints. Almost every stock aluminum control arm uses plastic or composite materials for the socket insert instead of a hardened metal socket. This is due to fretting corrosion where the two dissimilar metals wear and tear away at each other under loads and stress.
 
Once the insert is worn, the hardened stud will start to bite into the soft aluminum of the control arm. This can lead to catastrophic failure in a short period of time. The leading cause of the failure is typically failure of the protective boot. When the boot fails, water can wash out the lubricant and cause wear between the socket and stud.  
 
Some aftermarket suspension components have been engineered to use a metal-on-metal ball and socket; they also have the ability to be lubricated after installation.  
Fasteners
Aluminum components require special fasteners and tightening procedures to make sure they keep their tension and do not damage components. Typically, you will see coated threads, threadlockers and torque-to-yield (TTY) fasteners.    
 
TTY fasteners are mounting fasteners which are torqued beyond the state of elasticity and therefore undergo plastic transformation, causing them to become permanently elongated.
 
Conventional ball joints and tie-rod ends use a tapered stud and hole with a nut on top to secure the stud to the knuckle. The 7-10º angled taper, along with a threaded stud and nut, lock the components together by tensioning the nut and stud. TTY ball joint and tie-rod studs have two advantages. First, they can weigh less and still apply the same clamping loads. Second, the clamping loads are more consistent and controllable.
 
TTY fasteners were first used for engine head bolts because they required less torque, and the torque applied was more evenly distributed. This resulted in even clamping forces on the head gasket and less distortion in the block and head.
 
Some of the first TTY head bolts were used on bi-metal engines with aluminum heads and cast iron blocks. The same is true for suspensions; the first vehicles to use TTY studs used aluminum knuckles like on the Corvette. Now these types of ball joints and tie-rod ends can be found on Buicks, Jeeps and Fords. Also, more bolts for shock mounts, bushings and control arms are now using TTY fasteners. They are also used in vehicles with cast-iron knuckles. 
 
The metallurgy and heat treatment of TTY bolts and regular bolts is different, and you can sometimes tell one from the other by their appearance. TTY ball joints and studs have an inset hex head at the end of the stud. This can be used when tightening to the specified torque and setting the torque angle.
 
Always make sure to check the service information to get the right torque for a suspension component no matter what type of fastener. If you see an initial torque spec along with an angle in degrees, it is a TTY fastener.
 
Aluminum knuckles, upper control arms and ball joints can be damaged if not tightened using the correct procedure. Knuckles and upper control arms are aluminum and can be damaged if a torque wrench and torque angle gauge are not used. No matter if you go too tight or too loose, if you fail to use correct tools and procedures, you could be buying the customer a knuckle and working for free to install it.
 
Many ball joints may have an initial torque spec as low as 15-30 ft.-lbs. and torque angles are between 140º and 225º. Never guess or try to use your calibrated elbow; always look up the spec and use a torque wrench.
 
The same procedure is also required for tie-rod ends. Make sure the washers on the studs are in good condition and installed in the right direction. If a washer splits or fails, it could cause a catastrophic failure.
 
TTY ball joints and tie-rods are usually installed dry. Do not apply any oil, grease, assembly lube or sealer on the stud or tapered bore. The reason is lubricants reduce friction when a bolt is tightened. This actually increases the torque load on the bolt or stud, which may overload and stretch a TTY bolt too far, causing it to break.
The most important tightening procedure is to look up the torque values and procedures. Never guess or take short cuts when dealing with fasteners on aluminum components.  

You May Also Like

Embracing Cutting-Edge Solutions the Industry has to Offer

Embracing cutting-edge solutions is strategic and imperative for technicians navigating the constantly changing landscape of automotive maintenance and repair.

Nadine Battah

Remember last month how I said 2024 was your year to be the technicians you always wanted to be? Remaining stagnant as a technician is simply not an option anymore if you want to be successful in the automotive industry. You must proactively seek out opportunities to embrace new tools, techniques and solutions that promise to enhance efficiency, accuracy and customer satisfaction.Embracing what’s new is strategic and imperative for technicians navigating the constantly changing landscape of automotive maintenance and repair.One of the top reasons I can give you for embracing new technology is the potential for improved diagnostic accuracy and efficiency. With the arrival of advanced diagnostic tools, like the Bosch ADS 625X, the Autel IA900, or the Hunter ADASLink, technicians can pinpoint issues with precision, reducing guesswork and minimizing the risk of a comeback. Whether it’s sophisticated tools or cutting-edge software solutions, the ability to leverage these new tools should empower you to deliver next-level service and drive positive repair experiences for your customers.Another thing to keep in mind is that embracing new technology and equipment opens doors to expanded service offerings. From state-of-the-art lifts and alignment systems, to specialized tools designed for specific makes and models, investing in the latest equipment enables you and other technicians to tackle a larger range of repairs and maintenance with confidence and precision. As the technology in cars continue to evolve, so too must the tools and equipment that technicians rely on to get the job done.Embracing new technology and equipment can also lead to improved productivity in the shop. By leveraging high-quality products that are specifically designed for today’s vehicles, you can streamline workflow, minimize downtime and deliver exceptional results for your customers.At TechShop, we understand the importance of embracing new technology, equipment and products in the automotive repair industry. That’s why we’re excited to announce the debut of our all-new “Tool Time” video podcast series, where guests from brands like Ingersoll Rand, Clore Automotive, SATA Spray Equipment and many more will sit down and join Eric Garbe and myself to discuss education and training on the latest products our industry has to offer.Join us as we embrace the future of automotive tool supply and equipment advancements together. And, be sure to subscribe to the TechShop newsletter to stay tuned!

Brake Lathe Basics

Resurfacing drums and rotors is a machining process with its own specific guidelines.

Refrigerant Oil Has to Be Right

Oil type is just as important as oil capacity.

Three bottles of refrigerant oil
Top 5 Tools: Steve Coffell, Auto World, Hazelwood, MO

Steve Coffell, a technician at Auto World in Hazelwood, MO, says his Top 5 Favorite Tools are: Related Articles – Lisle 61860 Oil Filter Housing Torque Adapter – Mueller Kueps Presents Redesigned Sensor Tap Series – Lisle Low Profile Fuel Line Disconnect   OTC Genisys Touch – Quick scan, bidirectional control Snap-on VANTAGE Pro –

Wheel Bearing Adjustment Tools & Equipment

A wheel bearing that’s out of adjustment can reduce bearing life and can affect more than just the bearing. It’s important to adjust the wheel bearing endplay to the proper specifications. If the bearing set is adjusted too loose or too tight, it can cause the bearing to fail prematurely. There are a few types of assemblies, so using correct procedures and tools will ensure a comeback-free wheel bearing installation.

Other Posts

TPMS: Are Retrofits in Your Future?

Installing a retrofit kit can be performed with the tools and equipment you already own and use on a daily basis.

Tire tread
Maximize Your Scan Tool

Are you maximizing your scan tools to their full potential? Don’t let them be just an expensive code reader.

Scan Tool
2024 Is Your Year to Be the Technician You Always Wanted to Be

As we enter 2024, strategic career planning is essential for success in the automotive repair industry.

happy new year 2024
Impact Wrench Technology

Interchangeable anvils are a feature on some new impacts.